Passenger seats in commercial airplanes are generally arranged in rows, with one seat directly behind the other. When there is a sudden severe deceleration, a passenger is thrown forward against the lap restraint and the passenger's head moves in an arc downward and forward and usually impacts the seat back directly ahead. In the case of a seat row facing a bulkhead, the passenger's head strikes the bulkhead instead of a seat.
To protect passengers from head injury, the Federal Aviation Administration (“FAA”) has established a head injury criterion (“HIC”) set forth in 14 CFR 23.562 and 25.562. The formula for HIC from the foregoing regulation is reproduced in Formula (1) below:
                    HIC        =                              {                                                            [                                                            1                                                                        t                          2                                                -                                                  t                          1                                                                                      ⁢                                                                  ∫                                                  t                          1                                                                          t                          2                                                                    ⁢                                                                        a                          ⁡                                                      (                            t                            )                                                                          ⁢                        dt                                                                              ]                                2.5                            ⁢                              (                                                      t                    2                                    -                                      t                    1                                                  )                                      }                    max                                    (        1        )            Wherein:
t1 is the initial integration time in seconds;
t2 is the final integration time in seconds;
a(t) is the resultant deceleration at the center of gravity of a passenger's head in units of gravity.
HIC is normally derived based upon data from an accelerometer mounted at the center of gravity of an anthropomorphic test dummy's head in crash testing. It is an attempt to measure the likelihood of head injury resulting from an impact. When there is potential contact with adjacent seats, structure, or other items in an aircraft, 14 CFR 23.562(c)(5)(i) and 25.562(c)(5)(i) requires the provision of protection such that head impact does not exceed an HIC of 1000. At an HIC of 1000, there is an 18% probability of severe head injury occurrence in an average adult and a 55% probability of serious injury.
The risk of severe head injury tends to increase when the passenger's head strikes rigid, unyielding structure in the seat back or bulkhead. One type of rigid, unyielding, structure often found on the back of seatbacks, are display monitors. Commercial passenger aircraft for longer flights commonly have display monitors mounted on the back of each seat to provide entertainment for passengers and aircraft information. For passengers in rows facing bulkheads, the display monitor is usually mounted to the surface of the bulkhead directly ahead of each facing seat.
A display monitor typically includes metal components, such as a frame or chassis supporting an electronic visual display panel, such as a liquid crystal display (“LCD”). Supported behind the LCD are additional metal components, such as a rear support plate and electronics for receiving display signals and producing images on the electronic visual display panel. In addition, the display monitors are typically mounted with bolts or screws to relatively rigid or unyielding structure in the seat or bulk head so that the display monitor is securely held.
Due to the layout in most passenger aircraft, the display monitors generally lie in the path of travel followed by a passenger's head in the event of sudden severe deceleration. When a passenger's head impacts such an arrangement due to a sudden deceleration, the risk of head injury is increased due to the rigidity of the structure and resulting elevated HIC values.
In addition, 14 CFR 23.785, 25.785 and 29.785 requires a design that is free of potentially injurious objects, sharp edges, protuberances, and hard surfaces in an emergency landing as a result of the dynamic conditions specified in 14 CFR 23.562, 25.562 and 29.562. The requirement is such that a person making proper use of the equipment will not suffer serious injury. Hence it is further desirable that should a passenger's head strike a monitor display due to a sudden deceleration event, that the display not shatter or project sharp edges or protuberances as a result of impact.
Attempts have been made to provide monitor displays that as whole offer less rigidity in an impact. However, the result has generally been a monitor display that undergoes substantial deformation and causes brittle material, such as glass, to break and leave sharp edges exposed. Increasing rigidity tends to decrease the likelihood of exposed sharp edges, but has an adverse affect on HIC value. Embodiments of monitor displays in accordance with the present invention address these competing design goals by improving the interface between a monitor display and the structure to which it mounts.